Adult Upperparts plain brown, sometimes with a faint olive tinge. The pointed wings show extensive rufous throughout the primaries and outer secondaries that is visible both in flight and when perched. The long, graduated tail is plain brown or olive-brown on the upperside of the central tail feathers; the remaining tail feathers are blackish with large, bold white tips (visible in flight, from below when perched, or when the tail is spread). The underparts are uniformly whitish, sometimes with a faint buff wash on the belly and undertail coverts. The underwing coverts are whitish or buffy-white. The crown, forehead, ear coverts, and nape are plain brown or grey-brown, similar in colour to the upperparts, and contrast sharply with the whitish chin and throat; the lores and area around the eye are darker dusky-grey or dusky-brown and form a slight mask. The iris is dark, the orbital ring is yellow, the slender, decurved bill is yellow with a blackish culmen, and the legs and feet are dark grey.
Juvenile This plumage is held into the first fall but is lost through the first winter. It is similar to the adult plumage, but the outer tail feathers are greyer and with more diffuse, less well-defined, greyish-white spots at the tips of the feathers and extending up along the shaft. In addition, juvenal plumage averages somewhat duller than that of the adult, with a stronger buff wash on the throat and breast. Very young juveniles (June-August) have a largely greyish bill and orbital ring, but by late summer the bare part colouration becomes similar to that of the adult.
The Yellow-billed Cuckoo is very distinctive relative to other species in British Columbia, and only the Black-billed Cuckoo (which is also a vagrant) has a similar size, structure, and plumage pattern. Black-billed Cuckoo differs from the Yellow-billed Cuckoo in a number of features, including its more slender and wholly dark (grey and black) bill, its red (or, in juveniles, greenish) orbital ring (vs. yellow in Yellow-billed Cuckoo), its lack of rufous in the flight feathers, its buffy-tinged underparts (underparts of Yellow-billed are noticeably whiter), and the much smaller white tips to the tail feathers (as seen from below or in flight).
The most commonly-heard call of the Yellow-billed Cuckoo is a guttural, hard, knocking, wooden-sounding notes: ku-ku-ku-ku-ku-kow-kow-kowlp-kowlp-kowlp-kowlp. The initial series of ku or ka notes is given more rapidly than the terminal series of kowlp or kddowl notes. Also gives a rapid, harsh, rattled series of notes (kow-kow-kow-kow-kow-kow) that is reminiscent of the sound of a metal door knocker hitting a metal plate. Additional calls include a soft, deep, dove-like cloom or coo that is repeated in series with long pauses, and a slow, descending, weakening series of cooing notes (too too too too too to to to to).
This species is a vagrant to the province and does not breed, although it was historically a breeding species on the south coast.
This species relies heavily on large insect prey throughout the spring and summer, such as katydids, grasshoppers, cicadas, and crickets, and is a major predator of caterpillars (especially tent caterpillars). Other food items that are consumed on a more opportunistic basis include birds’ eggs and nestlings, small lizards, and small frogs. Seeds, fruits, and berries form a minor component of the diet during the breeding season but become more important during winter and migration. Foraging birds spend large amounts of time perched inconspicuously within the forest canopy, waiting for potential prey to expose themselves, rather than actively seeking out prey. Some birds, however, forage in a more active manner, pursuing and gleaning prey from the surface of leaves, twigs, and bark. Occasionally hawks for flying insects during short sallies, and sometimes descends to the ground to pursue prey on foot through low vegetation.
Source: Hughes (1999)
During the breeding season, the Yellow-billed Cuckoo is primarily associated with open, brushy deciduous woodlands, riparian groves, overgrown orchards, woodlots, parks, and abandoned farmlands. Vagrants to B.C. (as well as extirpated breeding populations) have been found in similar habitats, including riparian deciduous stands (cottonwood, willow, birch), coastal alder groves, forest edges, wooded suburbs, and orchards. This species formerly bred in the extensive riparian cottonwood stands and willow thickets of the lower Fraser River valley.
Source: Campbell et al. (1990b); Hughes (1999)
This species breeds widely across the eastern United States, from the Atlantic coast west to the Great Plains, ranging north into southern Ontario and southern Quebec. Farther west, the Yellow-billed Cuckoo breeds locally in the southwestern United States (primarily Arizona and New Mexico) as well as in small, isolated populations in Utah, Wyoming, Idaho, Montana, and California. It also breeds in northern Mexico, the Yucatan Peninsula, and the Caribbean. Winters primarily in South America.
Vagrancy Casual spring and very rare summer and fall vagrant across southern B.C., with records spanning the period between late April and early November; most records have occurred during the late June to mid-July and mid- to late October periods. Records of this species have occurred primarily on Vancouver Island and throughout the southern interior north to Revelstoke and the Kamloops area. There is a single record for the central mainland coast (Bella Coola) in August.
Source: Campbell et al. (1990b)
Population and Conservation Status
Although currently considered a vagrant to B.C., the Yellow-billed Cuckoo was a regular breeding species on the south coast of the province (as well as along the Pacific coast of the United States) at least into the 1930s or 1940s and may even have been fairly common. Habitat loss and fragmentation due to agricultural, urban, and hydroelectric development, along with the species’ limited dispersal and recolonization abilities and its reliance on large insect prey (which were reduced through pesticide use), appear to have contributed to a catastrophic population decline throughout all of western North America throughout the early 20th century. This decline rtesulted in the extirpation of this species from Oregon, Washington, and southwestern British Columbia, as well as most other areas throughout the western United States. This species is currently rare and extremely local in California, which is currently the only area along the Pacific coast with a breeding population.
Recently, however, the Yellow-billed Cuckoo has begun to appear more frequently as a vagrant throughout the Pacific Northwest, including British Columbia, and it is possible that the species may be in the early stages of reoccupation of its former breeding habitats. For example, this species went unrecorded in British Columbia between the late 1920s (which is shortly before its presumed extirpation from the province) and the late 1980s. Since 1989, however, records of this species in B.C. have been made with increasing frequency, and it has been reported nearly annually (sometimes with more than one record per year) since 2004. Furthermore, several of these records, especially in the Okanagan Valley of the south-central interior, have come from excellent breeding habitat during the height of the breeding season. It may be premature to suggest that the species is once again breeding in the province, but there is at least an indication that it may do so in the future if current trends continue.
Source: Campbell et al. (1990b); Hughes (1999)
Two subspecies of Yellow-billed Cuckoo are currently recognized, although they are weakly differentiated and not likely identifiable in the field. The subspecies that occurs locally in the western United States and which formerly bred in southwestern B.C., C.a.occidentalis, averages slightly greyer on the upperparts and (especially) the crown than the eastern C.a.americanus, with a more orange-tinged lower mandible and slightly larger average measurements (especially the wings and tail). Although C.a.occidentalis formerly bred in British Columbia, it may not necessarily be the source of all recent vagrants to the province, and some may in fact pertain to vagrants of the much more abundant and widespread C.a.americanus. Unfortunately, given the extreme similarity of the two subspecies it may be very difficult, if not impossible, to determine the true source of vagrants to B.C.
This species is very closely related to the Pearly-breasted Cuckoo (Coccyzus euleri) of South America, and the two are sometimes considered conspecific. Although this species is not particularly closely related to the Black-billed Cuckoo, these two species have hybridized on at least one occasion in the eastern United States.
Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2021. E-Fauna BC:
Electronic Atlas of the Fauna of British Columbia [efauna.bc.ca]. Lab
for Advanced Spatial Analysis, Department of Geography, University of British
Columbia, Vancouver. [Accessed:
2023-10-02 1:44:39 PM]
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